HONOLULU (AP) — A false alarm that warned of a ballistic missile headed for Hawaii sent the islands into a panic Saturday, with people abandoning cars in a highway and preparing to flee their homes until officials said the cellphone alert was a mistake.

Hawaii officials apologized repeatedly and said the alert was sent when someone hit the wrong button during a shift change.

On Saturday afternoon, Hawaii's Governor, David Ige, Administrator Miyagi and other officials spoke to reporters about the error and vowed the mistake would not happen again.

Governor Ige described the incident as "an inadvertent mistake" that occured during one of the three daily shift changes. "We will be looking at how we can improve the procedures so it doesn’t happen again," Ige pledged, adding, "It should not have happened.”

The emergency alert, which was sent to cellphones, said in all caps, 'Ballistic missile threat inbound to Hawaii. Seek immediate shelter. This is not a drill.'

Hawaii Emergency Management Agency spokesman Richard Repoza said it was a false alarm and the agency is trying to determine what happened.

About 10 minutes after the initial alert, Hawaii EMA tweeted there was no threat, but that didn't reach people who aren't on the social media platform. A revised alert informing of the "false alarm" didn't reach cellphones until 38 minutes later, according to the time stamp on images people shared on social media.

The alert caused a tizzy on the island and across social media.

Jamie Malapit, the owner of a Honolulu hair salon, texted his clients that he was canceling their appointments and was closing his shop for the day. He said he was still in bed when the phone started going off "like crazy." He thought it was a tsunami warning at first.

"I woke up and saw missile warning and thought no way. I thought 'No, this is not happening today,'" Malapit said.

He was still "a little freaked out" and feeling paranoid even after hearing it was a false alarm.

"I went from panic to semi-panic and 'Are we sure?'" he said.

The White House said President Donald Trump, at his private club in Florida, was briefed on the false alert. White House spokeswoman Lindsay Walters said it "was purely a state exercise."

Hawaii House Speaker Scott Saiki said the system residents have been told to rely on failed miserably. He also took emergency management officials to task for taking 30 minutes to issue a correction, prolonging panic.

"Clearly, government agencies are not prepared and lack the capacity to deal with emergency situations," he said in a statement.

Hawaii U.S. Sen. Brian Schatz tweeted the false alarm was "totally inexcusable" and was caused by human error.

"There needs to be tough and quick accountability and a fixed process," he wrote.

Federal Communications Commission Chairman Ajit Pai said on social media the panel would launch an investigation.

With the threat of missiles from North Korea in people's minds, the state reintroduced the Cold War-era warning siren tests last month that drew international attention. But there were problems there, too.

Even though the state says nearly 93 percent of the state's 386 sirens worked properly, 12 mistakenly played an ambulance siren. At the tourist mecca of Waikiki, the sirens were barely audible, prompting officials to add more sirens there and to reposition ones already in place.